<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Registry
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Registry.php 16207 2009-06-21 19:17:51Z thomas $
 */

/**
 * Generic storage class helps to manage global data.
 *
 * @category   Zend
 * @package    Zend_Registry
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Registry extends ArrayObject
{
	/**
	 * Class name of the singleton registry object.
	 * @var string
	 */
	private static $_registryClassName = 'Zend_Registry';

	/**
	 * Registry object provides storage for shared objects.
	 * @var Zend_Registry
	 */
	private static $_registry = null;

	/**
	 * Retrieves the default registry instance.
	 *
	 * @return Zend_Registry
	 */
	public static function getInstance()
	{
		if (self::$_registry === null) {
			self::init();
		}

		return self::$_registry;
	}

	/**
	 * Set the default registry instance to a specified instance.
	 *
	 * @param Zend_Registry $registry An object instance of type Zend_Registry,
	 *   or a subclass.
	 * @return void
	 * @throws Zend_Exception if registry is already initialized.
	 */
	public static function setInstance(Zend_Registry $registry)
	{
		if (self::$_registry !== null) {
			require_once 'Zend/Exception.php';
			throw new Zend_Exception('Registry is already initialized');
		}

		self::setClassName(get_class($registry));
		self::$_registry = $registry;
	}

	/**
	 * Initialize the default registry instance.
	 *
	 * @return void
	 */
	protected static function init()
	{
		self::setInstance(new self::$_registryClassName());
	}

	/**
	 * Set the class name to use for the default registry instance.
	 * Does not affect the currently initialized instance, it only applies
	 * for the next time you instantiate.
	 *
	 * @param string $registryClassName
	 * @return void
	 * @throws Zend_Exception if the registry is initialized or if the
	 *   class name is not valid.
	 */
	public static function setClassName($registryClassName = 'Zend_Registry')
	{
		if (self::$_registry !== null) {
			require_once 'Zend/Exception.php';
			throw new Zend_Exception('Registry is already initialized');
		}

		if (!is_string($registryClassName)) {
			require_once 'Zend/Exception.php';
			throw new Zend_Exception("Argument is not a class name");
		}

		/**
		 * @see Zend_Loader
		 */
		if (!class_exists($registryClassName)) {
			require_once 'Zend/Loader.php';
			Zend_Loader::loadClass($registryClassName);
		}

		self::$_registryClassName = $registryClassName;
	}

	/**
	 * Unset the default registry instance.
	 * Primarily used in tearDown() in unit tests.
	 * @returns void
	 */
	public static function _unsetInstance()
	{
		self::$_registry = null;
	}

	/**
	 * getter method, basically same as offsetGet().
	 *
	 * This method can be called from an object of type Zend_Registry, or it
	 * can be called statically.  In the latter case, it uses the default
	 * static instance stored in the class.
	 *
	 * @param string $index - get the value associated with $index
	 * @return mixed
	 * @throws Zend_Exception if no entry is registerd for $index.
	 */
	public static function get($index)
	{
		$instance = self::getInstance();

		if (!$instance->offsetExists($index)) {
			require_once 'Zend/Exception.php';
			throw new Zend_Exception("No entry is registered for key '$index'");
		}

		return $instance->offsetGet($index);
	}

	/**
	 * setter method, basically same as offsetSet().
	 *
	 * This method can be called from an object of type Zend_Registry, or it
	 * can be called statically.  In the latter case, it uses the default
	 * static instance stored in the class.
	 *
	 * @param string $index The location in the ArrayObject in which to store
	 *   the value.
	 * @param mixed $value The object to store in the ArrayObject.
	 * @return void
	 */
	public static function set($index, $value)
	{
		$instance = self::getInstance();
		$instance->offsetSet($index, $value);
	}

	/**
	 * Returns TRUE if the $index is a named value in the registry,
	 * or FALSE if $index was not found in the registry.
	 *
	 * @param  string $index
	 * @return boolean
	 */
	public static function isRegistered($index)
	{
		if (self::$_registry === null) {
			return false;
		}
		return self::$_registry->offsetExists($index);
	}

	/**
	 * Constructs a parent ArrayObject with default
	 * ARRAY_AS_PROPS to allow acces as an object
	 *
	 * @param array $array data array
	 * @param integer $flags ArrayObject flags
	 */
	public function __construct($array = array(), $flags = parent::ARRAY_AS_PROPS)
	{
		parent::__construct($array, $flags);
	}

	/**
	 * @param string $index
	 * @returns mixed
	 *
	 * Workaround for http://bugs.php.net/bug.php?id=40442 (ZF-960).
	 */
	public function offsetExists($index)
	{
		return array_key_exists($index, $this);
	}

}
